Five games into the Atlantic 10 season, Charlotte still is exceeding expectations.

The 49ers — picked to finish 12th in the preseason media poll — are tied atop the conference standings with a 4-1 record that nicely parallels their overall 16-3 mark. Their most recent victory, a 63-57 win at home against Xavier on Wednesday, was a bit of a milestone for most of the players on coach Alan Major’s team.

“I’ve never beaten Xavier, so this here was a big win,” said junior DeMario Mayfield, who scored 13 points in the victory. “Every win for us is a big win.”

Every Charlotte win is new territory under Major, who won 10 and 13 games in his first two rebuilding seasons with the program. As the preseason poll proved, the 49ers weren’t exactly expected to take such a big step forward this season. But here they are in late January, tied for first place in a league so deep that nine teams still harbor dreams of earning an NCAA Tournament at-large berth.

Charlotte, VCU, Xavier and Butler all have just one conference loss.

So, what has Major’s team done well en route to this sparkling record? And, can the 49ers stay near the top of the league and challenge for their first NCAA Tournament appearance since 2005?

The 49ers’ weak non-conference schedule helped build the record, no doubt. Their only two non-con losses were to the only two Pomeroy top-100 teams they played (Miami, Florida State). But as they showed with a nine-point win against La Salle in their A-10 opener—the very good La Salle team that beat No. 9 Butler on Wednesday—the 49ers are not completely a product of their schedule.

Charlotte’s success this season starts with defense. The 49ers hold opponents to an effective field-goal percentage of just .423, which is 11th in the country. They’re deep—nine players average at least 15 minutes per game—and the front line might not be exceptionally tall, but it’s rugged.

The defense must carry the 49ers the rest of the way because they’re not much of an offensive team. Their adjusted offensive rating (96.1) is last in the Atlantic 10, and their 3-point shooting (26.6 percent) is 336th of 347 Division I teams. Senior Chris Braswell leads Charlotte at 11.6 points per game, and Mayfield is right behind at 11.4.

The 49ers’ relatively slim NCAA Tournament prospects—the selection committee abhors weak non-conference schedules, which places Charlotte in a big hole—almost certainly will be determined with a brutal five-game stretch in February: at Temple, vs. VCU, at Butler, at Saint Louis, vs. Temple. Those are opportunities for quality victories, but the 49ers could play well and still finish that run 0-5.

Charlotte isn’t the only team playing surprisingly well in a non-BCS conference. Here’s a quick look at a few others:

SOUTHERN MISS

Conference: Conference USA.

Record: 16-4 (5-0).

Even if you haven’t noticed Southern Miss’ outstanding start to the season, you probably noticed the score of the Golden Eagles’ game Wednesday night. After Marshall opened with a first-possession 3-pointer, the Golden Eagles embarked on an insane 47-4 run over the next 14 minutes. They led 53-17 at half and wound up with a 102-46 victory against a team predicted to finish five spots higher than Southern Miss in Sporting News’ preseason C-USA rankings.

The prediction wasn’t unreasonable. Coach Larry Eustachy left for Colorado State after eight seasons at Southern Miss—last year’s 25-9 record was his best at the school—and four of the Golden Eagles’ top five scorers were gone. But former Morehead State coach Donnie Tyndall has done a masterful job getting production up and down a deep roster (10 players averaging at least a dozen minutes per game). Senior transfer Dwayne Davis, a bruising 6-5 forward, leads the team with 13.3 points per game.

The big challenge: To win the Conference USA title, they Golden Eagles must dethrone Memphis. They’ll get their first opportunity at home on Feb. 9. Any NCAA Tournament prospects rest with beating the Tigers at least once; they’re the only conference team other than Southern Miss in the Pomeroy top 100.

BRYANT

Conference: Northeast.

Record: 13-5 (6-1).

This has been an all-around amazing season for coach Tim O’Shea’s Bulldogs, who topped their 2011-12 win total by the end of November. Bryant finished 2-28 last season (1-17 in the Northeast Conference) but was rising an eight-game win streak before sustaining a tough road loss Thursday night at Sacred Heart. And the Bulldogs even pulled off a signature victory for the program, an 80-79 win over Lehigh on Dec. 29, despite future NBA first-round pick C.J. McCollum’s 34 points.

Bryant — picked to finish 10th in preseason — sits atop the league standings by a full game.

The Bulldogs are done with their five-year NCAA reclassification; as a full-fledged Division I program now, they’re eligible for NCAA Tournament play should they win the Northeast Tournament. Just because they’re eligible doesn’t mean much on the court, though. The high-scoring trio of Dyami Starks (17.8 points per game), Alex Francis (16.3) and Frankie Dobbs (13.9) makes Bryant a threat to actually get there.

The big challenge: Robert Morris, which beat MAC favorite Ohio in December, is the primary challenger to the league title. Bryan won the first meeting, 84-77, on Jan. 3 and the rematch is set for Feb. 28.

LOUISIANA TECH

Conference: WAC.

Record: 17-3 (8-0).

The WAC coaches and media couldn’t agree on the preseason conference favorites—the coaches went with Utah State and the media chose New Mexico State—but they did agree that Louisiana Tech didn’t have much of a chance. The Bulldogs didn’t get a single first-place vote and finished fourth in both polls. Heading into their road game Saturday against an injury-decimated Utah State squad, though, Louisiana Tech is in sole possession of first place, two games clear of the field in the loss column.

The Bulldogs have taken quite a big step in coach Michael White’s second year at the helm; Louisiana Tech needed a late-season push (7-2 in its final nine games) just to finish over .500 for the year, at 18-16.

This year’s team thrives on both creating turnovers (WAC-best 25.4 percent turnover rate, according to kenpom.com) and preventing turnovers (WAC-best 16.7 percent turnover rate); the latter number is especially impressive considering they play at the quickest pace in the league—an adjusted tempo of 70.9 possession per game.

The big challenge: The Bulldogs already have beaten their primary contenders for the regular season title—home wins against Denver (68-60) and New Mexico State (81-72)—and don’t face either again until March.